Most
cases of nonalcoholic fatty liver disease (NAFLD) and
nonalcoholic steatohepatitis (NASH) are suspected on
the basis of the exclusion of viral, autoimmune, metabolic
and genetic causes of chronic liver disease in patients
with chronic elevation of aminotransferase enzymes.
However, the definitive diagnosis of NASH requires liver
biopsy. Valuable blood tests include hepatitis B and
C serology, iron profile, alpha 1-antitrypsin phenotype,
ceruloplasmin, antinuclear antibody and antismooth muscle
antibody, and serum protein electrophoresis. If these
tests are negative or normal, and if there are no symptoms
or signs of chronic liver disease, it is unlikely that
a specifically treatable liver disease would be discovered
at biopsy. The prevalence of NAFLD in the general population
appears to be approximately 20%, and 2% to 3% of people
have NASH. There is no proven specific therapy for the
spectrum of nonalcoholic liver disease; therefore, the
management of the patient with NASH is not likely to
be changed after histological assessment. Bleeding,
sometimes fatal, and other complications requiring hospitalization
can occur, and liver biopsies should not be undertaken
without clear clinical indications. The high cost of
undertaking histological assessment of all persons with
asymptomatic elevations of liver enzymes cannot be justified
in view of the risks and limited clinical benefits.